Truss forming apparatus



United States Patent [72] Inventor Adolph ll. Lubin 718 S. 7th St.,Springfield, Illinois 62703 211 Appl. No. 767,744 [22] Filed Oct. 15,1968 [45] Patented Nov. 10, 1970 [73] Assignee Rose and Robert L. Lubin,executers of said Adolph l-l. Lubin, deceased [54] TRUSS FORMINGAPPARATUS 13 Claims, 12 Drawing Figs.

[52] U.S. Cl 100/53, 100/100, I00/209. 100/210; l44/288: 27/152, 269/321[51] Int. Cl B30b 15/14 [50] Field of Search 227/152; 269/321F;l44/288.6; 100/53, 100,209, 210

[56] References Cited UNITED STATES PATENTS 3,255,943 6/1966 Sanford227/152 3,390,628 7/1968 Sanford 100/100 3,464.348 9/1969 McGlinchey100/210 Primary Examiner-Billy J. Wilhite Attorney-Dawson, Tilton,Fallon and Lungmus ABSTRACT: A machine is described for securingtogether separate wood members by means of nail plates to form acompleted truss in one step, The machine includes a large, elongated,flat bed of high strength concrete for supporting the individual membersof the truss in a desired configuration.

Nail plates are placed above and beneath the abutting locations of eachof the individual truss members to overlap adjacent edges. A carriage ismounted at the sides of the bed for travel along the bed; and itincludes a first roller mounted for rotation about a horizontal axisextending transverse of the direction of travel of the machine forrolling over the wood members formed into the desired trussconfiguration and driving the nail plates to a first predetermined depthinto the wood members. A second, similar roller is mounted to thecarriage; and it follows the first roller for completely driving the topand bottom nail plates into the truss members to thereby firmly secureindividual members together in the desired truss configuration. Thecarriage is power-driven; and the same source of power drives therollers about their axes during operation, Electrical circuitry permitsstarting, stopping and reversing of the carriage.

Patented No 10, 1970 4 3,538,843

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Patented No.10,1970 3,538,843

FIRST ROLLER SECOND ROLLER TRAVEL DIRECT/0N J/(MZK 061% 1/ TRUSS FORMINGAPPARATUS BACKGROUND AND SUMMARY The present invention relates to atruss-forming machine; more particularly, it relates to a system forforming completed trusses in a single operation.

Trusses have long been used as structural, weight supporting members inbridges and the like; but only comparatively recently have theadvantages of wooden trusses in residential construction been fullyappreciated. The principle use of trusses in residential constructionis, of course, in the support of peaked roofs, in which case a number ofspaced-apart trusses are supported by the walls. Trusses as used inresidential construction are formed by cutting the individual, separatemembers from construction lumber of the size and shape required, andthen securing abutting edges of the separate members together in thedesired truss configuration by means of nail plates.

An early method of forming trusses of the type with which the presentinvention is concerned requires the use of metal horses equipped withclamping mechanisms for holding the individual members in the desiredtruss configuration; and an operator pulls a hydraulically powered presswith flat, opposing jaws extending in horizontal planes to each locationat which a nail plate is to be driven into the abutting truss members.The members; and he then moves the hydraulically-actuated press over thejunction area. When the operator actuates the trigger, the jaws cometogether and drive the nail plate into the truss member. Thus, theoperator is required to move the presses (which conventionally issuspended from a con-.

versely of the direction of travel of the gantry to form a support forthe truss being formed. The tables are adjustably spaced along thedirection of the rails; and each table includes a heel pad forsupporting the truss at the particular location at which a junction ofindividual members is to be made. Thus, in setting up a trussconfiguration, the tables have to be adjusted along the direction oftravel of the gantry to selected locations for supporting the individualmembers being joined; and heel pads on each table have to be moved tothe correct lateral location to lie beneath the junction.

Each of the junctions are then clamped to the heel pad; the nail platesare placed above the separate truss members, and the gantry is drivenover the truss to drive the nail plates partially into the wood members.After the first set of nail plates are partially embedded in the truss,the truss is moved from its setup and placed on a conveyor belt to asecond location at which the nail plates were fully driven into thetruss.

It will be realized that the total number of truss configurations is ofgreat magnitude, and that it is desirable to have a truss machinecapable of efficiently and economically producing small numbers oftrusses without additional and lengthy setup procedures before a run canbe made. Setup was complicated by the need to space the tableslongitudinally of the truss and to separately locate the heel pads alongthe width of the table at the location at which junctions were to bemade. Aside from the cumbersome setup procedure required of the priormachine, it had the further disadvantage that the trusses had to beconveyed to a separate location before the nail plates could be fullydriven into the truss member.

The present invention provides a flat, integral bed of very highstrength concrete for supporting the individual truss members in adesired configuration with nail plates located below and above eachjunction to be formed. The bed provides sufficient area to support aplurality of truss members to form anumber of trusses (of the same ordifferent configurations) at the sarne time. A plurality of channels areformed longitudinally of the concrete bed in which lock members arereceived for locking the individual truss members in the desiredconfiguration for formation.

A carriage is supported at each side of the bed for movement along thebed and over the formed truss. A first roller is mounted in the carriageto press both the top and bottom nail plates into the truss members to apredetermined depth (which is less than the height of the nail prong) tostart the nail plates into the wood truss member. A second roller islocated in the carriage behind the first roller to fully drive the nailplates into the truss members and thus complete the formation of thetruss. A third roller is also housed in the carriage at the same heightas the previously-described first roller so that the carriage may formtrusses while being driven in either direction.

It will thus be appreciated that the present system does not require thespacing of separate tables for supporting the individual trusses in thedirection of travel of rollers. Secondly, there is no. need for the heelpads of the previously-described commercialized machine for supportingthe unsecured truss at the juncture and locking the same place.

The height of the pressing rollers above the bed is independentlyadjustable so that the system may be adapted for trusses of differentdepths. Further, the adjustability of the initial or lead roller hasbeen found to be advantageous in adapting the machine to all makes andgauges of nail plates and to further accommodate differences in density,penetration resistance, etc. of the woods encountered. The inventivesystem accommodates trusses of any configurations without the need tomake adjustment of the supporting member. The flexibility of thearrangement used to lock the separate truss members into the desiredconfiguration permits a set up with a minimum of adjustment. Further,the size of the bed permits the formation of several trussconfigurations, not all of which need be of the. same configuration. Thesame apparatus could readily be adapted to form wall panel assemblies,both interior and exterior of various lengths.

Other features and advantages of the present invention will be apparentto persons skilled in the art from the following detailed description ofa preferred embodiment accompanied by the attached drawing whereinidentical reference numerals will refer to like parts in the variousviews.

THE DRAWING FIG. 1 is a perspective view of a truss-forming systemaccording to the present invention;

FIG. 2 is a close-up view of a setup for the formation of the truss;

FIG. 3 is an exploded view of a junction of individual truss memberstogether with a detailed view of the truss locking mechanism;

FIG. 4 is a detailed view of a nail plate as seen in FIG. 3;

FIG. 5 is a side elevation view of the carriage and roller assemblytogether with the drive mechanism;

FIG. 6 is a detailed plan view of the adjustable roller mountmg;

FIG. 7 is a detailed elevation view of the roller mounting and the driveshaft;

FIG. 8 is a longitudinal cross section view of a roller;

FIG. 9 is a transverse cross section view of the table;

FIG. 10 is a perspective view of the lock mechanism for securing thetruss in place;

FIG. 11 illustrates the operation of the lead and follower roller toform a truss; and

FIG. 12 is a circuit schematic diagram of the electrical system forcontrolling the apparatus of FIG. 1.

DETAILED DESCRIPTION Referring now to FIG. I, there is in perspectiveview a system incorporating the present invention. The system of FIG. 1includes a table having an elongated, flat bed generally designated byreference numeral which is integrally made with and carried by asupporting base 11 which rests on the ground. The bed or platform 10 isformed of high strength concrete, as disclosed in greater detail within.Rails 12 and 13 are rigidly secured to the elongated side edges of thebed 10. A driven carriage, generally designated 15, is mounted on theside rails 12 and 13 for rolling along them, as presently discussed.

The frame for the carriage 15 includes a pair of vertical side plates 18and 19 which are secured together at their upper sections by crossbars20 and 21. The side plates 18 and 19 are secured together at a lowerlocation by means of transverse crossbars 22 and 22a (FIGS. 1 and 5) toform a very rigid structure adapted for movement longitudinally of thebed 10.

As seen clearly in FIG. 9, the bed 10 rests on a base of concrete asindicated by reference numeral 25. The base 25 is made from a highstrength concrete of the order of 4,000 psi. The bed 10 preferablyincludes a covering layer 10a of abrasion-resistant concrete such as isavailable under the tradename Metalicorn. The side rails 12 and 13 areC-shaped in cross section, having inwardly-extending upper and lowerflanges as at 12a and 12b, and 13a and 13b, respectively, for providingsteel surfaces along which the rollers are drive wheels (describedlater) supporting the carriage 15 may ride.

Embedded in the upper surface of the bed 10 are a plurality oflongitudinal channels generally designated by reference numeral inFIG. 1. The channels 30 are located at equallyspaced increments alongthe width of the bed 10; and each of the channels 30 extend for the fulllength of the bed 10. Referring now to FIG. l0, one of the channels 30is seen in greater detail to include a ll-shupcd conduit member 3|defining an open upper track 32. The upper, side edges of the channelmember 3] are provided with downwardly-turned flanges 33. Arectangular-shaped nut 34 is provided with tapered, serrated groovesalong opposite edges of its upper surface for receiving thedownwardly-turned flanges 33 of the channel member 31 and locking thenut 34 to the channel member when an upward force is inserted on the nut34. A spring 34a interposed between the bottom of the channel 31 and thenut 34 resiliently urges the nut 34 into the upper position and therebyfacilitates access to nut 34. Preferably, in horizontal cross section,the nut 34 is rectangular having its longest dimension transverse of thegrooves 35 so that when the nut 34 is turned at a right angle, it may beremoved from the channel member 31 through the open track 32 while atthe same time, the nut 34 may be adjusted longitudinally of the channelmember 31 to any desired position.

The nut 34 defines a vertical, threaded aperture 38 for receiving athreaded bolt 39. Rotatably mounted on the neck of the bolt 39 is anL-shaped angle brace generally designated 40, and including a horizontalportion 41 and an upstanding portion 42 for engaging and holding a trusssupported on the bed 10 of the machine.

Referring again to MG. 1, it will be appreciated that each of theChIlllflClH 30 may be provided with a nurnher of similar nuts, bolts andangle lH'ttClwlN for locking a truss in pluc'e after initial setup andprior to driving the carriage over the truss. The locking systemdescribed including the channels and fittings is distributed by UnistrutCorporation, Wayne, Michigan.

It will be appreciated that various modifications of the lock memberdescribed as well as alternatives to the overall locking mechanism maybe equally effectively employed for locking the truss in place. One suchmodification is shown in FIG. 3 wherein a flat bearing plate 45 havingan integral handle 46 replaces the previously-described angle bracket40. The bearing plate 45 defines a contact surface 47 for engaging thesides of the wood members of the truss; and the contact surface 47 maybe curved and eccentrically formed about the pivotal connection betweenthe bolt 39 and the bearing plate 45; so that as the handle 46 isrotated in a direction of the arrow in FIG. 3, the surface 47 is broughtinto engagement with the wood member 48 which is an individual memberforming the final truss.

FIGS. 2 and 3 illustrate in greater detail a setup which might beemployed for a typical truss configuration. The base member of the trussis designated 49; and the nail plates are designated 50. It will beappreciated from a full understanding of the invention that thedimensions or gauge of the nail plates employed is not critical, andthat nail plates having different areas may simultaneously be employed.A detailed view of a nail plate 50 is seen in FIG. 4 to include a flatpiece of sheet metal 51 from which a plurality of prongs 52 are cut andbent to assume a position perpendicular to the plane of the plate 51.The prongs 52, of course, form the nails; and the plate 51 serves toprovide a brace uniting the individual truss members (such as themembers 48 and 49 of FIG. 3) at a junction where the two wood membersabut. After the individual members of the truss are laid out in properrelation on the bed 10, nail plates 50 are placed above and beneath eachof the junctions of separate members to overlap the abutting edges. Thetruss is then locked into place by means of the previously-describedlocking members, which, it will be remembered, are slidably adjustablealong the channel members 31.

Referring now to FIGS. 57, three pressing rollers are designated 55, 56,and 57 respectively. A convention will be made that the forwarddirection of the rollers 5557 is to the right in FIG. 5; so that theroller 55 will be sometimes be referred to as the forward roller, theroller 56 as the center roller, and the roller 57 as the rear roller.

Each of the pressing rollers 55-57 is similar in construction; and,referring to FIG. 8, the roller 57 is seen to include a shaft 60 and acylindrical sleeve 61 which provides the surface which drives the nailplates into the truss member. The sleeve 61 may be heavy-wall type pipestock. A plurality of baffle plates 62 extend radially of the shaft 60and are spaced longitudinally along it. The plates 62 are plug-welded asat 63 to the cylindrical pipe 61. The baffle plates 62 are also weldedas at 64 to the shaft 60. End plates 65 secure the ends of the pipe orsleeve 61 to the shaft 60; and further reinforcement is provided by endblocks 66 of heavier stock which end blocks also serve as mountingmembers for sprockets (not shown in FIG. 8).

Referring in particular to FIG. 5, each of the pressing rollers 55-57 issecured to their respective side plates 18 and 19 of the carriage 15 ina similar fashion, and hence, only one such mounting need be describedin detail for a complete understanding of themachine. Toward this end,the mounting for the forward roller 55 will be more fully explainedpresently.

The plate 18 defines a slot 68 which is elongated in the verticaldirection for receiving a shaft 69 of the roller 55. The shaft 69extends through the side plate 18 and is received in a roller bearing70, as best seen in FIG. 6. The bearing 70 includes a casing 71 which isreceived by means of side slots in two vertical hearing guides 73 and74. The hearing guides 73 and 74. The bearing guides 73 and 74 arerigidly mounted to the plate [8 by mcnns of angle irons 75 and 76 whichare welded to the outer surface of the plate IS. The bearing housing 7]is vertically slidable along the guides 73 and 74. Secured to the bottomof the angle irons.75 and 76 is an internally-threaded housing generallydesignated 77 which receives a threaded shaft 78 which is secured to thebearing housing 71 as at 79. The housing 77 includes a capstan which,when turned, withdraws or extends the threaded shaft 78 to move thebearing housing vertically to a predetermined location along the bearingguides 73 and 74. The means just described for permitting verticaladjustment of the shaft of the pressing roller while rigidly fixing thatposition relative to the bed 10 of the machine during operation iscommonly used and referred to as a type C elevator boot takeup and it isknown to have very great strength in tension so as to easily sustain theforce encountered in driving the nail plates into the wood truss member.

The side plate 18 also defines slots 81 and 82, similarly elongated inthe vertical direction for receiving the shafts of the center and rearpressing rollers 56 and 57 respectively. Elevator boot takeups,generally designated 83 and 84 in FIG. 6 are also provided formountingthe shafts of the pressing rollers 56 and 57 to the side plate 18 whilepermitting vertical adjustment thereof. Similar mountings are provided(though not illustrated) for the other side of each of the shafts of therollers 55-57 in securing them to the side plate 19.

A drive motor 90 including a conventional speed reducer,

coupling, and brake is mounted on the interior side of the plate 18 bymeans of a bracket 91 fastened to the bottom of supporting braces 92 and93. A sprocket 94 is mounted on the shaft of the motor 90; and it drivesa chain 95. The chain 95 is wound around a second sprocket 96 which isconnected to a main drive shaft 97. The drive shaft 97 is rotatablymounted by means of pillow blocks 97a to a bracket 98 which, in turn, isfastened to the side wall 18 by means of the mounting members 99. Theother side of the drive shaft 97 is similarly fastened to the other sidewall 19. A pair of sprockets, smaller than the sprocket 96 andidentified by reference numerals 100 and 100a in FIG. 7, are mounted onthe drive shaft 97. Second and third chains 101 and 102 are drivenrespectively by the sprockets 100 and 100a to drive the carriage and thepressing rollers. The chain 100 is fitted around a sprocket 104 which ismounted on the shaft 69 of the forward roller 55 by means of the endblock 66, as mentioned. The chain 100 is also wound about a sprocket 105which is rigidly connected to the shaft of the center roller 56 by meansofa similar end block. The chain 101 is also fitted about an idlersprocket 106 which is laterally adjustably mounted in a horizontal slot107 in theside plate 18. Similarly, the chain 102 is wound around anidler sprocket 108 laterally adjustable mounted in a horizontal slot 109in the side plate 18, a sprocket 110 connected tothe drive shaft of therear roller 57, and a sprocket 111 which is secured to the side plate 18by means of a bearing block 112 and a shaft 112a.

A drive wheel 113 (FIGS. 1 and 7) is also mounted to the shaft 112a sothat by driving the sprocket 111, the drive wheel 113 is rotated. Thedrive wheel 113 engages the top flange 12a of the side rail 12 of thebed 10. Thus, all of the rollers 55-57 as well as the carriage 18 aredriven by means of the motor 90. Since the drive shaft 97 extendsbetween each of the side plates 18 and 19, a similar device arrangementis provided (although not shown in detail) for driving the other side ofthe carriage l5.

Cam followers 115 and 116 are conventionally mounted to the inside ofthe side plate 18; and they are rotatable about a horizontal axisperpendicular to the plane of the page of FIG. 5 for engaging the lowerflange 12a of the rail 12 and preventing lifting of the side plate 18 asthe rollers press over the nail plates and wood truss members. A similarcam follower 117 is suitable mounted 'to engage the upper flange 12a ofthe side rail 12 directly above the forward lower cam follower 116 toachieve stabilitycAs seen in FIG. 7, a similar cam follower 118 issecured by means of the mounting plate 119 to the inside surface of theside plate 18 and rotatably mounted about a vertical axis to engage thevertical side surface of the side rail 12 and prevent lateral shiftingof the carriage 15. There are two such cam rollers (the other one beingdesignated 119a in FIG. 5) for each side plate of the carriage 15,although the two attached to the side plate 19 are not shown forbrevity.

OPERATION The operation of the above-described mechanical portion of themachine is best illustrated in FIG. 11 which is a vertical cross sectionview taken from the left side of the machine; and it is apparent thatthe illustration is condensed, having a midsection deleted. The roller55 is adjusted to a height whereby its lowest portion is at apredetermined height above the upper surface of the bed to drive the twoopposing nail plates 125 and 126 partially into the wood truss member127. After the sufficient to press the plate portions of the nail platesand 126 into contact with the truss member 127, continues to drive thenail plates 125 and 126 fully into the truss member 127. It is assumed,of course, that the nail plates 125 and 126 overlap to join togetherabutting portions, although only one individual truss member is shown. 7

Referring now to FIGS. 1 and 5', a safety feature is incorporated in thesystem to automatically shut down the motor which drives the carriageshould an object or obstruction'be encountered in front of the carriage.A first bumper 130 has a lead rail 131 which extends completelytransverse of the carriage 15 and lies in front of it. A similar bumpergenerally designated 132 and including a lead rail 133 (seen in FIG. 1in perspective) is attached to the rear of the carriage 15. The bumpers130 and 132 are suspended from the framing (crossbars 22 and 22a) of thecarriage by means of links 135 which are pivotally connected at 136 tothe crossbars. Thus, when either of the bumpers 130 or 132 engages anobstruction, it will pivot in the direction of the carriage 15. A firstcollision limit switch 138 having a contact arm engaging the rear of thebumper 32 is mounted to the crossbar 22 of the framing of the carriage15 to be closed when the bumper 132 encounters an obstruction.Similarly, a collision limit switch 139 having a wiper arm engaging therear rail of bumper 130 is connected to the transverse brace 22a to openwhen the same encounters an obstruction. As will also be observed inFIG. 1, there are a plurality of control boxes generally designated 140which are spaced longitudinally of the table 10 to permit an operator tocontrol the movement of the carriage 15 at any number of locations alongthe table. It is contemplated that for a bed length of 100 feet, sixsuch stations would be provided.

Turning now to FIG. 12, three input lines 141 are connected to aconventional three-phase, 60-cycle source of electricity (not shown). Athree-phase disconnect switch, generally designated by reference numeral142, is interposed in the lines 141. A fuse 143 is inserted in each ofthe lines 141. Forward/reverse contacts (controlled by separate relays)include three normally open contacts 145 one of which is connected ineach of the lines 141 for coupling the source to drive the motor 90(shown schematically in FIG. 12) in a forward direction, and threenormally open contacts 146 for reversing the phase in two of the sourcelines to reverse the direction of rotation of the motor 90. Thepreviously-described collision limit switches 138 and 139 are connectedin series with the coil ofa relay 147 across two of the power lines.Three normally open contacts 147a are connected in the main power lines141 between the forward/reverse contacts 145 and 146 and the three-phasedrive motor which is the previously-described drive motor 90. 'The motoris protected from thermal overload as at 148. When either of thecollision limit switches 138 or 139 is opened by its associated bumperencountering an object, the relay 147 will be deenergized to open thecontacts 147a and shut down the motor 90. A brake coil 90a for the motor90 is connected across two of the power lines 141 as is conventional.

The control circuitry for the individual control stations 140 spacedalong the table is energized by means of a transformer 150 having itsprimary connected across two of the power lines 141 and its secondaryfused as at 151 and 152. For purposes of illustration, it will beassumed that there are six of the independent control stations 140(identified by roman numerals I-VI in FIG. 12) spaced along the table,although only two such stations are shown in FIG. 1. In order tofacilitate the association of the components with each station, each ofthe stations will be represented respectively by the numerals 161, 162,163, 164, 165, and 166 with an accompanying letter to represent acircuit element at the station. Thus, a series of six stop push buttons161a, 162a, 163a, 164a, 165a, and 166a are connected in series, with oneterminal of the switch 161a connected to the fuse 151. The switches161a-I66a are emergency stop switches.

Each station is also equipped with an on/off switch; and these aredesignated respectively 161b, 1621), 163b, 164b, 165b, and 16612. Theswitches 161b166b are key-operated selector switches; and they have oneterminal connected in common to a terminal of the switch 166a. Theon/off switch for station 161 is illustrated as being closed while theothers are illustrated as being open; and each of the switches 16llb1661; may be manually set to an on" or an off position by means of thekey. Each of the individual stations is not activated until the switchis set to an onposition. Each station is also equipped with a forwardpush switch (designated respectively 161c-166c) and a reverse switch(designated 161d-166d respectively). The forward and the reverse pushswitches are spring return selector switches biased to the off position;and they each have one terminal connected to their respective on/offkey-operated switches. The other terminal of all of the forward switchesis connected in common to a normally-closed, movable right limit switch167. The reverse switches for each of the stations have their secondterminal connected in common and coupled to one terminal of anormally-closed, movable left limit switch 168. The movable right andleft limit switches may be located beneath the bed 10 so as to becontacted by the cam followers 115; and they may be placed at anylocation along the bed.

A right limit switch which is normally closed and designated byreference numeral 169 is connected in series with the normally-closedmovable right limit switch 167 and a normallyclosed pair of contacts 170controlled by the forward relay 171. A similar left limit switch whichis normally-closed and designated 174 is connected in series with themovable left limit switch 168 and a pair of normally-closed contacts 175which are actuated by a reverse relay 176. The other terminal of therelay coils 171 and 176 are coupled to the second terminal of thesecondary winding of the transformer 150. The forward relay 171 alsoactuates the forward contacts 145 interposed in the power lines 141; andthe reverse relay 176 also actuates the reverse contacts 146.Normally-closed contacts 177 and 178 are connected in series with theforward and reverse relays 171 and 176 to deenergize them when the motoris overloaded, according to conventional technique.

A normally-open set of relay contacts 150 which are controlled by theforward relay 171, are connected between the common junction of theon/off switches 16111-166b and the common terminal of the stationreverse" switches 161d 166d to short circuit all the individual stationreverse actuators when the carriage is moving in a forward directiomApair of normally-open contacts 181 which are controlled by the reverserelay 176 are connected between the common junction of the stationon/off switches 161d-166d and the common junction of the station forwardswitches 161c- 166c to similarly short circuit the station forwardswitches when the carriage is traveling in a reverse direction. Thus thecarriage must be fully stopped before its direction may be changed.

in operation, after the main disconnect switch 142 has been closed, atleast one of the station on/off switches 161b-166b (for example, switch16212) has been actuated to energize the appropriate'stations, when anoperator desires to move the carriage in a forward direction, one of thestation's forward push switches 161c 166c must be closed. When thisoccurs, current is coupled from the secondary of the transformer 151)through the series-connected stop switches 161a166a, through the stationon switch 162b, the station forward" switch 1620, the normally-closedmovable right limit switch 167, the normally-closed fixed right limitswitch 169 and the normally-closed contacts 170 to the coil 171 of theforward relay. When the relay 171 is energized, the contacts 145 areclosed and, providing the collision limits switches 138 and 139 are alsoclosed, the contacts 147a will be closed by relay 1457 to energize thedrive motor 90. During this time, the contacts 81) will also be closedto insure that the station reverse switches are shorted. At the sametime, the normally-closed contacts 175 will be open by the relay 171 toinsure that the relay 176 cannot be energized. Thus, the carriage willcontinue in a forward motion with either one of the stations stop pushswitches 161a- -166a is opened, or the movable right limit switch 167 isencountered, or the fixed right limit switch 169 is actuated.

The operation of the station reverse" switches 161d-li6td is similar butcomplementary; and it will be observed that when the reverse relay 176is energized, it controls a pair of normally-closed contacts 170inserted in series with the coil of the forward relay 171 to openthereby insuring that the forward relay 171 cannot be energized whilethe carriage is moving in a reverse direction. At the same time, thereverse" relay reverses the phase in two of the motor power leads 141 toreverse the stator current by means of the normally-open contacts 146.

Having thus described in detail a preferred embodiment of the presentinvention, it will be apparent to persons skilled in the art thatvarious modifications and substitutions may be made for the structureand circuitry which have been illustrated; and it is, therefore,intended that all such modifications and equivalents be covered as theyare embraced within the spirit and scope of the appended claims.

It is claimed:

1. Apparatus for securing together separate wood members by means ofnail plates to form a truss comprising: a table providing a flat bed forsupporting said separate members in a desired truss configuration with afirst nail plate located above and a second nail plate located belowabutting locations of said members and with the prongs of said nailplates in engagement with the upper and lower surfaces respectively ofsaid members; carriage means mounted to said table for travel along saidbed and including first roller means spaced from said bed at a distanceto drive said top and bottom nail plates into said truss members to afirst depth less than the height of said nail prongs, and second rollermeans on said carriage generally parallel with and behind said firstroller means and spaced from said bed at a second predetermined distancefor rolling over said top and bottom nail plates and said truss membersafter said first roller means to fully drive said top and bottom nailplates into said truss members; and power means for driving saidcarriage along said bed.

2. The apparatus of claim 1 further comprising lock means for lockingsaid truss members in a predetermined truss configuration and securing.

3. The apparatus of claim 2 wherein said lock means is connected to saidbed for securing said truss configuration thereto.

4. The apparatus of claim 3 wherein said lock means comprises aplurality of elongated tracks fixed in said bed at laterally-spacedapart locations and extending longitudinally thereof, at least one lookmember slidably received by each of said tracks for adjustmenttherealong and rigidly securable to said track at any selected locationalong said bed; and a contact member secured by each of said lockmembers in engagement with a truss member for limiting lateral movementthereof.

5. The apparatus of claim 1 wherein said power means includes anelectrical motor on said carriage and drive means powered by said motorand in frictional contact with said bed to drive said carriage alongsaid bed and further including control means for selectively drivingsaid carriage in either direction and for stopping motion thereof.

6. The apparatus of claim 1 further comprising third roller meansmounted on said carriage on the other side of a said second roller meansthan is said first roller means and parallel thereto, and spaced fromsaid bed at approximately the same distance as said first roller meanswhereby said carriage may form trusses in one pass in either directionof travel along said bed.

7. The apparatus of claim 6 further comprising lock means connected tosaid bed and adjustable therealong for securing individual members ofsaid truss to said bed in said desired configuration.

8. The apparatus of claim 7 wherein said bed includes a supportingsurface of high strength concrete of the order of 4000p.s.i. and saidlock members include track means embedded in said concrete of said bedfor slidably receiving said lock means to facilitate adjustment of saidlock means along said bed during set up of a truss configuration.

9. The apparatus of claim 8 wherein said bed further includes first andsecond side rails mounted respectively to opposite sides of said bed andextending in the direction of elongation of said bed, said carriagemounted for rolling along said rails.

10. The apparatus of claim 9 further comprising drive wheel meansrotatably mounted on said carriage and for frictional engagement withsaid bed, and coupling means for coupling the power of said motor todrive said rollers and said drive wheel means.

11. The apparatus of claim 7 further comprising control means forselectively driving said carriage in either direction and for stoppingthe same.

12. The apparatus of claim 11 wherein said control means comprises aplurality of control stations mounted at spaced in tervals along saidbed, each station including forward control means for driving saidcarriage in a first direction along said bed, interlocking circuit meansfor disengaging one of said forward drive means and said reverse drivemeans when the other is energized, and stopcircuit means for disengagingall of said forward andreverse drive means to thereby stop saidcarriage.

13. The apparatus of claim 1 further comprising adjustable means formounting each of said roller means to said carriage while permittingindependent adjustment of said distance between each roller and saidbed.

